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标题：First-principles calculations of equilibrium silicon isotope fractionation in metamorphic silicate minerals
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作者：Yuanhong Li ; Wenzhong Wang ; Chen Zhou 等
期刊名称：Solid Earth Sciences
印刷版ISSN：2451-912X
电子版ISSN：2451-912X
出版年度：2019
卷号：4
期号：4
页码：142-149
DOI：10.1016/j.sesci.2019.09.004
语种：English
出版社：Elsevier
摘要：In this study, silicon isotope fractionation factors for metamorphic silicate including muscovite, epidote, and kyanite are calculated using first-principles methods based on density-functional theory. The reduced partition function ratio (103 lnb) of 30Si/28Si decreases in the order of muscovite > epidote z kyanite. Combining with previous calculations, our results show that the equilibrium silicon isotope fractionation factors are correlated with average SieO bond length. These results predict that measurable Si isotope fractionation can occur during metamorphic fluid activities. At 1000 K, the calculated 103 lna values for quartzeepidote, quartzekyanite, and quartzemuscovite are 0.51‰, 0.49‰, and 0.08‰, respectively. The calculation results are generally consistent with the observed Si isotopic data in two metamorphic eclogite-vein systems, showing that our work can provide useful information in investigating the Si isotope fractionation in metamorphic fluid evolution.
关键词：KeywordsenSi isotopesFirst-principles calculationMetamorphic fluid